The present invention relates to a client/server system. More specifically, the present invention relates to an automatic maintenance technique for automatically maintaining a client under control of the client itself as well as a computer executing such self maintenance and a recording medium therefor.
In recent years, as the performance of general purpose computer such as a personal computer is enhanced, the client/server systems widely spread. Speaking of the client/server system, there are some cases where a user's operational error, simple environment setting error or the like tends to cause such a problem as to influence the overall network system. When the problem occurs, the server is incapable of sending a maintenance command to the client. In those cases, there is a fear that not only maintenance cannot be executed but also the system may become inoperable until the system is recovered. The fear grows as the number of clients connecting to the server increases. With the network system becoming larger, there is no ignoring economical damages this may cause.
Moreover, the infection of computer viruses is recently becoming a serious problem to the system using a plurality of general purpose computers as clients and a server such as a client/server system. Namely, when a computer virus enters a general purpose computer serving as one of the plural clients in the client/server system, then the virus spreads over all clients and the server via the network, thus entailing a big loss. Considering this, to comfortably operate the client/server system, it is vital to efficiently execute system maintenance.
Meanwhile, for the maintenance of respective clients in the conventional client/server system, there has been adopted a so-called top-down method, i.e., the method in which a user stores necessary information about maintenance in the server and a maintenance command is issued from the server. In this top-down method, however, the maintenance command is basically issued to all clients connecting to the server all at once. Owing to this, every time maintenance work is being done, excessive loads are imposed on the server and the transmission path. During that time, all clients is inoperative simultaneously, with the result that the overall system performance is disadvantageously lowered.
As can be understood from the above, the conventional client/server system requires maintenance work and the maintenance time largely depends on the maintenance capability of the server or the communication capability of the transmission path. When a problem occurs, clearing up the cause has to depend on the capability of the user or of maintenance personnel. As a result, not only the recovery of the system cannot be expected quickly but also this eventually troubles the user and maintenance personnel.
Under these circumstances, the inventor of the present application filed an invention identified as Japanese Patent Application Laid-Open No. 8-272643. According to the Japanese Patent Application Laid-Open No. 8-272643, self-maintenance capability is provided to clients, with which individual clients make self-diagnoses when powered, and only when some problem occurs, only necessary file(s) is downloaded from the backup system of the clients stored in the server and the self-repair processing is carried out. The Japanese Patent Application Laid-Open No. 8-272643 is thus designed to reduce loads imposed on the server and the transmission paths, to decrease the probability that the system becomes inoperative and to enhance the overall system capability by allowing the respective clients to execute self-maintenance.
Nevertheless, there are many cases recently where the size of software installed into clients is as large as that in units of 100 MB. This requires increasing the capacity of the memory of the server. In addition, when such software are downloaded from the server into the clients, the higher loads are imposed on the transmission paths. This causes the lowering of system response and many clients requiring maintenance have to wait due to delayed response. For that reason, when the number of clients increases, it is necessary to review the capability of the server and that of the transmission paths and to redesign them. In some cases, there is a fear that the number of the clients cannot be even increased.